Regarding David Barrow's config:
- I turned on Send Redundant PC's.
- I removed some unnecessary actions from buttons, including Momentary, IA Link, Send on Preset Change and Update on Preset Change.
- But the thing that probably did it were the two buttons on page 5: "2112" and "Burgs". These have different System/Preset commands (338 and 364), and Send on Preset Change was enabled for both. Which is faulty programming in the first place, but it shouldn't result in a bank switching error. After having removed Send on Preset Change on those buttons, the bank issue is now gone.
However, Soren Kelly's configuration doesn't appear to have a System/Preset at all, so whether it really is the culprit, I don't know.
I also searched Soren's configuration for an accidental CC#0 message (because he does use CC#1) and couldn't find it.
My own wrong bank issue disappeared after cleaning up my configuration including removing System/Preset buttons, and reappeared after I added it again. Might be a coincidence.
I cannot reproduce it reliably. The issue rears its ugly head only after a while. Might be a certain chain of events, or a timing issue.
But: things are starting to point towards the system write procedure. The bank issue seems to occur, or at least occur more often, after configuration changes have been written to the hardware. Even today, the issue happened twice after writing changes. Maybe that procedure messes up the bank data?
Now here's a c(l)ue: after the issue appeared, I executed "Write settings to device" (instead of Write Changes), and this solved the issue.